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Figure 4 | Respiratory Research

Figure 4

From: Reverse mode Na+/Ca2+ exchange mediated by STIM1 contributes to Ca2+ influx in airway smooth muscle following agonist stimulation

Figure 4

HBSMCs transfected with NCX1 siRNA have reduced NCX1 expression and display reduced HA mediated NCX1 outwardly rectifying currents. Reverse mode NCX1 was activated by re-addition of 2 mM extracellular Ca2+ and 10 μM HA. (A) Time course of NCX1 outward current density (at +80 mV) obtained by subtracting the current recorded in Ca2+-free solution; Control (diamonds, n = 13) and NCX1 siRNA (squares, n = 17). (B) Bar chart illustrating peak current density of NCX1 outwardly rectifying currents in cells transfected with either negative control siRNA (n = 13) or NCX1 siRNA (n = 17) (mean data ± SEM, *p < 0.05). C) Representative traces of current-voltage (I-V) relationships of NCX1 currents in cells transfected with control or NCX1 siRNA. D) siRNA targeted knockdown of NCX1 mRNA assessed by quantitative PCR. Cells transfected with 50 nM NCX1 siRNA reduced NCX1 mRNA levels (73.2 ± 2.2%, n = 4) with no effect on STIM1 expression. Note that in panel 4A baseline currents (0 Ca2+) have been subtracted from all traces.

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